hei,
Jeg har laget et lite C-program som gjør bruk av malloc og gratis for behandling punktgrafikkbilder. når jeg prøver å kjøre programmet, får jeg en feilmelding noe sånt

*** Glibc oppdaget *** gratis (): ugyldig neste størrelse (normal): 0x0000000000503e70 ***

Jeg er ikke sikker på hvilke ledig () er årsaken til feilen.

Kan noen av dere fortelle meg, hva er årsaken til dette? og hvordan kan jeg bli kvitt dette?

Hjelp vil bli verdsatt.

Linux 2.6.11.4-21,11-standard # 1 Sat Feb 2 20:54:26 UTC 2006 x86_64 x86_64 x86_64 GNU/Linux

gcc version 3.3.5 20050117 (prerelease) (SUSE Linux)

glatt GNU C Bibliotek stabile versjonen 2.3.4 (20050218), av Roland McGrath et al.

Her er en del av mitt program

main()
{
	struct tt
	{
		char a[54];
	}g;
	struct ss
	{
		int a[54];
	}e;
	char *f;
	char *b,*chr;
	long p=0,q=0,i=0,j=0;//,r=0;
	long r1=0,r2=0,z1=0,r3=0,r4=0;//width calculation
	int l=0;
	int k=0,flag=0,flag1=0,flag2=0;
        //char ch=' ';
	FILE *fp,*fp1;
	
	fp=fopen("paradise.bmp","rb");
	fp1=fopen("hi1.bmp","w");
	
	fread(&g,54,1,fp);
	for(i=0;i<=53;i++)
	{
		if(g.a[i]<0)
			e.a[i]=255+g.a[i]+1;
		else
			e.a[i]=g.a[i];
		printf(" %d ",e.a[i]);
	}
	r1=(e.a[18])+e.a[19]*256+e.a[20]*256*256+e.a[21]*256*256*256;
	printf("\n*******r1=%ld*********\n",r1);
	//cheking for zero padding
	if(r1%4==0)
	{
		printf("\n********r1=%ld******\n",r1); 
		//no change;
	}
	else if(r1%3==0)
	{
		z1=r1;
		flag1=2;
	}
	else if(r1%2==0)
	{
		z1=r1*2;
		//printf("\n********z1=%ld******\n",z1); 
		flag1=1;
	}
	else
	{
		//flag1=0;
	}
	r1=r1*2;
	r3=r1;
	r2=e.a[22]+e.a[23]*256+e.a[24]*256*256+e.a[25]*256*256*256;
	printf("\n*****r2=%ld******\n",r2); 
	r2=r2*2;
	r4=r2;
	printf("\n*****r4=%ld******\n",r4);
	printf("\nhi %d\n",r1);
	e.a[21]=(r1)/(16777216);
	printf("\nhi  ");
	g.a[21]=e.a[21];
	r1=r1-e.a[21]*256*256*256;
	e.a[20]=(r1)/(65536);
	g.a[20]=e.a[20];
	r1=r1-e.a[20]*256*256;
	e.a[19]=(r1)/(256);
	g.a[19]=e.a[19];
	r1=r1-e.a[19]*256;
	e.a[18]=r1;
	g.a[18]=e.a[18];
	e.a[25]=(r2)/(16777216);
	g.a[25]=e.a[25];
	r2=r2-e.a[25]*256*256*256;
	e.a[24]=(r2)/(65536);
	g.a[24]=e.a[24];
	r2=r2-e.a[24]*256*256;
	e.a[23]=(r2)/(256);
	g.a[23]=e.a[23];
	r2=r2-e.a[23]*256;
	e.a[22]=r2;
	g.a[22]=e.a[22];
	r1=e.a[2]+e.a[3]*256+e.a[4]*256*256+e.a[5]*256*256*256;
	r1=(r1-z1)*2;
	r2=r1;
	e.a[37]=(r1)/(16777216);
	g.a[37]=e.a[37];
	r1=r1-e.a[37]*256*256*256;
	e.a[36]=(r1)/(65536);
	g.a[36]=e.a[36];
	r1=r1-e.a[36]*256*256;
	e.a[35]=(r1)/(256);
	g.a[35]=e.a[35];
	r1=r1-e.a[35]*256;
	e.a[34]=r1;
	g.a[34]=e.a[34];
	e.a[5]=(r2)/(16777216);
	g.a[5]=e.a[5];
	r2=r2-e.a[5]*256*256*256;
	e.a[4]=(r2)/(65536);
	g.a[4]=e.a[4];
	r2=r2-e.a[4]*256*256;
	e.a[3]=(r2)/(256);
	g.a[3]=e.a[3];
	r2=r2-e.a[3]*256;
	e.a[2]=r2;
	g.a[2]=e.a[2];
	fwrite(&g,54,1,fp1);
	fclose(fp1);
	fclose(fp);
	printf("\n after calculation g.a[] is : ");
	for(i=0;i<=53;i++)
		printf(" %d ",g.a[i]);
	printf("\n hello");
	printf("\n******r3=%ld*****\n",r3);
	if((f=(char *)malloc(r3*3/4))==NULL)
	{
		printf("NO SPACE");
		exit(0);
	}
	printf("\n f[] is : ");
	for(p=0;p<r3*3/2;p++)
	{
		//*(f+p)=128;
		f[p]=128; 
		printf(" %c ",f[p]);
	}
	printf("\n");
	b=(char *)malloc(r3*3/4);
	for(i=0;i<=r4;i++)
	{
		fp=fopen("paradise.bmp","rb");
		if(i==0)
			fseek(fp,54,0L);
		else if((i+1)%2!=0 && flag1==1)
		{
			l++;
			fseek(fp,54+(r3*3/4)*i+(l)*2,0L);
		}
	   	else
			fseek(fp,54+(r3*3/4)*i+(l)*2,0L);
	        chr=(char *)malloc(r3*3/2);
	        fread(chr,r3*3/4,1,fp);
      //		if(i%2==0){
//			for(r=0;r<r3*3/4;r++)

	  //	}
		fflush(fp);
	   	fclose(fp);
		for(p=0;p<(r3*3/4);p++)
		{
		//	b[p]=e.a[p];
			//*(b+p)=*(chr+p);
			b[p]=chr[p]; 
		}
	   //job of this loop is to make e.a[] a 582 byte array
		for(p=0,q=0;p<(r3*3/4)*2;)
		{
			if(flag==1)
			{
			   for(k=0;k<=2;k++)
			   {
				//*(chr+p)=128;
				   chr[p]=128;   
				p++;
			   }
			   flag--;
			}
			else
			{
			   for(k=0;k<=2;k++)
			   {
				//*(chr+p)=*(b+q);
				   chr[p]=b[q];
				q++;
				p++;
			   }
			flag++;
			}
		}
	        fp1=fopen("hi1.bmp","a+");
	        if(j%4==0)
		{
		      fseek(fp1,54+j*(r3*3/4)*2,0L);
	//write linefeed code here
                      for(k=0;k<(r3/2)*3;k++)
		      {
			    if(chr[k]==10)// ||*(chr+k)==13)
				chr[k]=12;
		      }
                      fwrite(chr,(r3*3/4)*2,1,fp1);
		      j++;
	         }
	         else if((j-1)%4==0)
		 {
		      fseek(fp1,54+j*(r3*3/4)*2,0L);
	              for(k=0;k<(r3/2)*3;k++)
		      {
			   if(chr[k]==10 )//||*(chr+k)==13)
				chr[k]=12;
		      }
		      fwrite(chr,(r3*3/4)*2,1,fp1);
		      j++;
	         }
	         if(j%4!=0 && (j-1)%4!=0)
		 {
		       fseek(fp1,54+j*(r3*3/4)*2,0L);
		       fwrite(f,(r3*3/4)*2,1,fp1);
		       fwrite(f,(r3*3/4)*2,1,fp1);
		       j+=2;
	         }
		 fflush(stdin);
		 fflush(fp1);
		 fclose(fp1);
                 free(f);
                 free(chr);
		 free(b);
                 f=(char *)malloc(r3*3/2);
                 for(p=0;p<r3*3/2;p++)
                      f[p]=128;
	}
//}
	      	if(i%2==0){
	      	  for(k=0;k<=1;k++)
		       if(flag2==0){
			flag2=1;
			fwrite(&e,582,1,fp1);
		       }
		       else{
			fseek(fp1,55+582*1+582,0L);
			fwrite(&e,582,1,fp1);
			flag2=0;
		       }

		}
		else{
			fwrite(&f,582,1,fp1);
			flag1=2;
		}
			 

	if(i==2||i==34){
		if(i==34)
			fputc(48,fp1);
		else
			fputc(102,fp1);
		fputc(228,fp1);
		fputc(6,fp1);
		i=i+2;
	}
	else if(i==18 || i==22){
		fputc(132,fp1);
		fputc(1,fp1);
		i++;
	}
	else
		fputc(e.a[i],fp1); 
}

Du vil aldri kalle malloc å opprette b, linje 223 du ringe gratis (b)